Elevated low-density lipoprotein cholesterol (LDL-C) is a major residual risk factor among patients with acute coronary syndrome (ACS). In the absence of sufficient real-world evidence, this observational (noninterventional) study investigated the effectiveness and safety of evolocumab in patients with hyperlipidemia treated with evolocumab for ACS in a real-world clinical setting in Korea. Between January 2022 and February 2023, patients from 10hospitals in Korea who initiated evolocumab within 24weeks of an ACS event were enrolled. Data collected at visit1 (evolocumab initiation) included patients' characteristics, comorbidities, and lipid-lowering therapies. LDL-C reduction from visit1 (week0) to visit2 (week8) was assessed. The primary outcome was the proportion of patients who achieved LDL-C < 1.4mmol/L (55mg/dL) at follow-up; the secondary outcome was the proportion who achieved LDL-C < 1.8mmol/L (70mg/dL) at follow-up. In this study, 89 out of 142 enrolled patients were included in the effectiveness analysis. The mean (SD) age of the included patients was 59.3 (12.3) years, with the majority being male (87.6%). Sixty-one patients received statin-ezetimibe combination therapy (68.5%). The median [Q1, Q3] LDL-C level at the start of the study was 2.5 [2.0, 3.0] mmol/L (98 [77, 115] mg/dL), which decreased to 1.3 [0.7, 1.7] mmol/L (49 [29, 67] mg/dL) after 8weeks of evolocumab treatment, resulting in an mean (SD) 50.9 (28.6) % reduction and 1.4 (1.0) mmol/L (55.1 (37.9) mg/dL) absolute reduction. At follow-up, 55.1% and 78.7% of patients achieved LDL-C goals of < 1.4mmol/L (55mg/dL) and < 1.8mmol/L (70mg/dL), respectively. No adverse or serious adverse drug reactions were reported. Evolocumab treatment was associated with significant LDL-C lowering and favorable safety and guideline-recommended LDL-C goal achievement rates among patients with ACS in the real-world clinical practice setting in South Korea.